Use of 6-(trifluoromethyl)hydrouracils as herbicides

ABSTRACT

1. A METHOD FOR THE CONTROL OF UNDESIRABLE PLANT SPECIES COMPRISING APPLYING TO A LOCUS TO BE PROTECTED FROM SAID PLANT SPECIES A HERBICIDALLY EFFECITVE AMOUNT OF AT LEAST ONE COMPOUND REPRESENT BY THE FORMULA:   2,4-DI(O=),3-R2,5-X,5-Y,6-R1,6-(F3C-)-HEXAHYDROPYRIMIDINE   WHEREIN X IS SELECTED FROM THE GROUP CONSISTING OF HALOGEN AND LOWER ALKYL OF C1-C4; Y IS HALOGEN; R1 IS SELECTED FROM THE GROUP CONSISTING OF HALOGEN, HYDROXY, ALKOXY OF C1-C6, AND MONO- AND DI-HALOALKOXY OF C1-C6; AND R2 IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN; ALKYL OF C1-C6; ALKENYL OF C2-C6; MONO- OR DI-SUBSTITUTED ALKYL OF C1-C6 HAVING A SUBSTITUENT SELECTED FROM THE GROUP CONSISTING OF HALOGEN, HYDROXY AND LOWER ALKOXY OF C1C4; PHENYL; CYCLOHEXYL; CYCLOPENTYL; AND MONO- OR DI-SUBSTITUTED PHENYL HAVING A SUBSTITUENT SELECTED FROM THE GROUP CONSISTING OF NITRO, HALOGEN, LOWER ALKOXY OF C1-C4, MONO- OR DI-HALOALKOXY OF C1-C6 AND TRIFLUOROMETHYL, AND TASSIUM AND AMMONIUM SALTS OF SAID COMPOUNDS AND TAUTOMERS, WHEREIN SAID HALOGEN AND HALO SUBSTITUENTS ARE SELECTED FROM THE GROUP CONSISTING OF FLUORINE, CHLORINE, BROMINE AND IODINE.

United States Patent "ice 3,843,348 USE OF 6-(TRIFLUOROMETHYL)HYDROURACILS AS HERBICIDES Albert William Lutz, Montgomery Township, Somerset County, and Richard William Fecny, Hightstown, N..l., Zssignors to American Cyanamid Company, Stamford,

onn.

N0 Drawing. Original application Mar. 17, 1970, Ser. No. 20,382, now Patent No. 3,669,770. Divided and this application Feb. 16, 1972, Ser. No. 226,959

R is halogen, hydroxy, alkoxy or haloalkoxy; and R is hydrogen, alkyl, substituted alkyl, phenyl, cyclohexyl, cyclopentyl, substituted phenyl, or alkenyl.

CROSS-REFERENCE TO RELATED APPLICATION This application is a divisional of application Ser. No. 20,382, filed on Mar. 17, 1970, now U.S. Pat. 3,669,970 (1972).

CROSS-REFERENCE TO RELATED APPLICATION U.S. Pat. 3,322,526 relates to substituted hydrouracils of the formula:

wherein groups R -R are broadly defined. This patent also suggests that such compounds exhibit herbicidal activity and proposes four methods for the preparation of compounds of the above formula. However, it should be noted that the patentee does not contemplate the 6- halo, 6 hydroxy, 6-alkoxy, or 6-haloalkoxy-6-(trifiuoromethyl)hydrouracils of the present invention or a method for their manufacture.

3,843,348 Patented Oct. 22, 1974 He does suggest four methods for the preparation of his dihydrouracils. These include catalytic hydrogenation of a uracil of the formula:

Ilia Ilia R5 o to yield 11 o the dihydrouraeil -R1 wherein R is stated to be hydrogen, alkyl or alkoxy. Since this reaction adds hydrogen across the double bond, it does not lend itself to preparation of compounds of the present invention.

The second method of the patentee suggests cyclization of a substituted fi-arnino propionate with an isocyanate. The reaction is illustrated as follows:

If this reaction was to be employed for the preparation of the compounds of the present invention, R in the #3- amino propionate would have to represent trifluoromethyl and R would have to be halo, hydroxy, alkoxy or haloalkoxy. To the best of applicants knowledge these compounds have not been disclosed in the literature and no method for their preparation has been suggested.

The third method proposed by the patentee involves the reaction of a substituted urea with an a, fl-unsaturated acid as illustrated below:

' u RINHCNHZ Rag Again, the prior art appears to be devoid of a d-unsaturated acids of the above formula in which R is trifluoromethyl, R is halo, hydroxy, alkoxy or haloalkoxy and R is halogen or alkyl. It also appears to be devoid of methods for making such compounds.

The fourth and final method described by the patentee for preparing his dihydrouracils involves exchange of certain functional groups without disturbing the dihydrouracil nucleus. The reaction is illustrated as follows:

This final method, like those previously described, also fails to describe or anticipate the present invention, for heretofore the intermedaite compounds necessary to prepare the patentees starting materials, i.e. 6-(trifluoromethyl)-uracils of the formula:

wherein X is selected from the group consisting of halogen and lower alkyl;

Y is halogen;

R is selected from the group consisting of hydroxy,

alkoxy, halogen, and haloalkoxy; and

R is selected from the group consisting of hydrogen, alkyl, alkenyl, substituted alkyl, phenyl, cyclnhexyl, cyclopentyl, and substituted phenyl.

The compounds of this invention may also exhibit tautomeric forms as shown by way of example below:

Such tautomeric structures are included with the scope of the invention as are the water soluble salts, particularly the sodium, potassium, and ammonium salts, of the compounds and tautomers.

The various groupings referred to hereinabove may be more particularly identified as follows:

The term halogen means fluorine, chlorine, bromine or iodine.

The term alkyl means a monovalent radical derived from a straight or branched chain aliphatic hydrocarbon be removal of one hydrogen atom and having 1 to 6 car bon atoms. Illustrative members include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl, and hexyl.

The term lower alkyl has the same meaning as alkyl but contains only from 1 to 4 carbon atoms.

The term alkenyl means unsaturated straight and banched hydrocarbon monovalent radicals containing from 2 to 6 carbon atoms. Illustrative members are allyl, Z-butenyl and 2-methylallyl.

The term alkoxy means a monovalent R O-radical where the R group is an alkyl of from 1 to 6 carbon atoms; illustrative members are methoxy, ethoxy, propoxy, butoxy, pentoxy, and heXoXy.

The term haloalkoxy means an alkoxy radical containing either 1 to 2 halogen substituents and where there are 2 substituents they may be the same or different; illustrative members are 2-chloroethoxy, 3-bromopropoxy, dichloromethoxy, and 2,3-dibromopropoxy.

The term substituted alkyl means an alkyl radical as defined above wherein 1 or 2 hydrogens are replaced by a substituent selected from the group consisting of halogen, hydroxy, and lower alkoxy (i.e. an alkoxy group having from 1 to 4 carbon atoms). Where there are two substituents they may be identical or dissimilar; illus trat ive members are 2-methoxyethyl, 3-rnethoxypropyl, 2- bromopropyl, 4-chlorobutyl, 2-hydroxyethyl, and 4-hydroxybutyl.

The term substituted phenyl means a phenyl radical in which 1 or 2 of the hydrogen atoms are replaced with a substituent selected from the group consisting of nitro, halogen, lower alkoXy, haloalkoxy and trifluoromethyl. Where there are two substituents they may be identical or dissimilar; illustrative members are Z-nitrophenyl, 3,4- dichlorophenyl, 2,4-dichlorophenyl, m-trifiuoromethylphenyl, Z-methoxyphenyl, and 4-dichloromethoxyphenyl.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Compounds The following compounds are illustrative of the compounds of this invention (numbered in accordance with formula I):

5 ,5 -dichloro-6-hydroxy-3-isopropyl-6- (trifiuoromethyl hydrouracil;

5 ,5 -dichloro-3-isopropyl-6-methoXy-6- trifluoromethyl hydrouracil;

5 ,5 -dichloro-6-ethoxy-3-isopropyl-6- trifluoromethyl hydrouracil;

3-sec-butyl-S,5-dichloro-6-methoXy-6- (tritiuoromethyl hydrouracil;

5,5 -dichloro-3-isopropyl-6-pr0poxy-6- (trifluoromethyl) hydrouracil;

5 ,5 -dibromo-6-hydroxy-3-isopropyl-6- (tritiuoromethyl hydrouracil;

5 ,5 -dichloro-6-methoxy-3-phenyl-6- (trifluoromethyl hydrouracil;

S-bromo-S-chloro-3-isopropyl-6-methoxy-6- (trifluoromethyl) hydrouracil;

5 -bromo-5 -chloro-6-hydroxy-3-isopropyl-6- (trifiuoromethyl) hydrouracil;

5 ,5 -dichloro-6-methoxy-3-methyl-6- (trifluoromethyl hydrouracil;

5 ,5 ,6-trichloro-3-isopropyl- 6-(trifluoromethyl) hydrouracil;

5-chloro-6-methoxy-3-methyl-5-methyl-6- (trifluoromethyl) hydro uracil;

Reaction (D) employs the reaction product of (A) and involves contacting said product with a thionylhalide to yield the 3-substituted-6-halo-6-(trifluorOmethyDhydrouracil (V). This reaction is graphically illustrated below:

(Ill) where z is halogen.

We have found that these reactions (A through D) are generally exothermic and that the temperature at which each of said reactions is carried out is critical. While temperatures between about 25 and 60 C. gen erally give optimum efiiciency, such reactions may be carried out over a wider temperature range as, for example, between about 15 C. and 75 C. In any event, the reaction temperature must be maintained sufiiciently high to permit hypohalous acid or organic hypohalites to add across the double bond of the uracil but below that temperature at which hypohalite is liberated from the hydrouracil formed. In practice said reactions will generally be conducted at atmospheric pressure, however, subatmospheric and superatmospheric pressures may be used if desired. It has also been determined that an inert solvent such as benzene, chloroform or carbon disulfide may be used in reactions (A-D) without adversely effecting product yield. This practice, however, is generally most advantageously employed where the reaction mixture tends to be viscous, i.e. in reactions utilizing the higher alcohols or the halogenated higher alcohols.

As will become apparent from the examples set forth below, reaction (A) yields formula (I) hydrouracils wherein R is hydroxy; (B) yields similar compounds in which R is alkoxy; (C) yields like compounds where R is haloalkoxy and (D) provides the formula (I) compounds in which R is fluorine, chlorine or bromine. Moreover, from the appended examples it will also become apparent that in reactions (A), (B) and (C) when W in the formula (II) compound represents hydrogen, X and Y in the formula (III) hydrouracil are the same and represent the halogen employed in the reaction. However, when W represents a halogen which differs from the halogen (Y) added to the reaction mixture, a hydrouracil with mixed halogens at the 5 position is formed, X rep- 60 resenting the halogen W and Y the halogen added. Similarly, where W is lower alkyl, such as methyl, ethyl, propyl, isopropyl, butyl or sec butyl, the hydrouracil with a lower alkyl and a halogen at the 5 position is formed.

Reactants R1- N R2 wherein R is halogen, lower alkyl or hydrogen, R is lower alkyl and R is alkyl, substituted alkyl, phenyl, cyclohexyl, cyclopentyl, substituted phenyl or alkenyl. In the case where the R substituent of the compounds of this invention is hydrogen, the required starting materials (II) are either available to those skilled in the art or else can be prepared from available materials in accordance with procedures known to those skilled in the art such as, for example, that reported by Kaiser and Burger in J. Org. Chem. 24, 113 (1959).

Solvents particularly adapted to use in these reactions are the 1 to 8 carbon alcohols such as methanol, ethanol, propanol, octanol, t-butanol, and the like; the glycol others such as diethylene glycol dimethylether, ethylene glycol dimethylether, ethylene glycol diethyl ether and the like; and dipolar aprotic solvents such as dimethylsulfoxide, dimethylformamide, methyl isobutyl ketone, N,N-dimetl1- ylacetamide, and the like.

Among the bases which are suitable for use in these reactions are potassium-t-butoxide, sodium methoxide, sodium hydride, potassium hydroxide, pentamethylguanidine, potassium hydride and sodium metal. The reactions may be carried out over a wide temperature range of from about 15 C. to C., with a preferred range of about 25 C. to 50 C. It has also been found that about 1.0 moles to 1.5 moles of base per mole of reactant provide optimum product yields.

Utility The inventive compounds are potent pre and post emergence herbicides as amply shown by the illustrative data of Examples 1 through 4 lereinbelow.

The herbicidal compositions of the present invention may be prepared as solutions of water soluble salts, as emulsifiable concentrates, dusts, dust concentrates and wettable powders which lend themselves to application with conventional spraying and dusting equipment.

Representative formulations which may be prepared are provided below (percentages are by weight):

Aqueous solution Percent 5,5-dichloro 3 isopropyl-6-methoXy-6-(trifluoromethyl)hydrouracil 22.5 Triethylamine 8.0 Water (a lower alcohol such as methanol, ethanol or the like may also be used as cosolvent) q.s. 100

Emulsifiable concentrate Percent 5,5-dichloro 3 isopropyl 6 methoxy-6- (trifluoromethyl)hydrouracil 25 Nonionic-anionic emulsifier (mol 77L [by Wm.

Cooper and Nephers]) l0 Methylisobutylketone 65 (Dispersed in water for application).

Wettable powder 1 I l I l l l I Percent 5,5-dichloro 6 ethoxy 3 isopropyl--(trifluoromethyl)hydrouracil 50 m l I I I I I Wetting agent-oleic acid ester of sodium isothio- 5 3 nate 3.0 Dispersant-sodium salt of polymeric carboxyhc g l l l I l I I acid Attaclay 3 m I new e 5,5-dibromo-6-hydroxy 3 isopropyl-G-(tnfiuoro- 10 w methyl)hydrouracil 80 O Oleic acid ester of sodium isothionate (Igepon l AP-78) 1 8 Sodium salt of polymeric carboxylic acid (Tamol I m I I am I 3 g cum 0: Kaolinite 16 O In practice the compositions of the invention may be I; l 5 E E used to control a wide variety of monocotyledonous and Q dicotyledonous plants. They may be used for both post- 0 m I I I I I I I emergence and pre-emergence control of plants by applicap. tion to plant foliage or to soil containing seeds or other propagules of plants and find particular utility as selective 0 post-emergence and pre-emergence herbicides. As selec- 3 tive post-emergence herbicides they are especially useful r g Wm cm for controlling broadleaf weeds and grasses in the presence f; of crops such as corn, cotton and sorghum. As selective o pre-emergence herbicides they are especially useful for m em controlling weeds and grasses in the presence of crops m 0 such as corn, sorghum, soybeans, lima beans, cotton, peas, string beans watermelons cucumbers squash and um a s a P P In a: kin. S

The following examples are provided to further illus- E H I trate the invention. d

EXAMPLE 1 p O3 @0208 6503c Postemergence herbicidal activity H 2 m The postemergence herbicidal activity of the com- Q pounds of the present invention is demonstrated by the g following tests wherein a variety of monocotyledonous 40 Q and dicotyledonous plants are treated with test coms. pounds dispersed in aqueous-acetone mixtures. In the tests seedling plants are grown in jiify flats for about two 6 c M: I I I weeks. The test compounds are dispersed in 50/50 ace- 0 tone/water mixtures in sutficient quantity to provide the equivalent of about 0.125 to 10 pounds per acre of active 2 I I compound when applied to the plants through a spray nozzle operating at 30 p.s.i. for a predetermined time. a

er spraying, t e p ants are p aced on greenhouse a I. benches and are cared for in the usual manner, com- E mensurate with conventional greenhouse practices. Two 2 M l weeks after treatment, the seedling plants are examined 0 and rated according to the Herbitoxicity Index provided & below. The data obtained are reported in Table I. E 1

Herbitoxicity Index 9=100% reduction in stand. s=SevereinjI1ry. 5 am I mm 1 9=1 or 2 stunted plants remainm=Moderate injury.

ing. t=Traee to slight injury. 8=85100% reduction in stand. -=No test. 0 0: mg r FI 7 =7085% reduction in stand. c= Chlorosis. 1% g '5 6==60-70% reduction in stand. g= Growth retarded. 0 E151 5=50-60% reduction in stand. a=Abnonnal growth. E' :9. 4=4050% reduction in stand. r= Regrowth. 3=3040% reduction in stand. 2=20-30% reduction in stand. 1 10-20% reduction in stand. 0=No apparent effect.

Plant Abbreviations g :5 AW=Alligator weed. WO=Wild oats. '3 :3 m BW=Bindweed. MI=Millet. n1 0 9 CT=Ganada thistle. PF=Parrots feathers. o E El JG=Johns0n grass. COR=Oorn. E Q U NS=NI1tsedge. OOT=Ootton. 0 o o I QG=Quackgrass. SOY=Soybean. o l z )[Z KO=Koehia. SB=Sugar beets. L LA=Lambs quarters. TO=Tomato. l lZ O m2 Mu=Mustard. WH=Wheat. G m2 I I I -I PI=Pigweed. RA=Radish. E BA=Barnyard grass. LB=Lima beans. O 9. 6 CR=Crabgrass. SG=Sorghum. 5 Q m 0 o I; m E. GRF=Greenfoxta1L O [:1 o Q Q III Gab

one

O HO .1 5 EXAMPLE 2 Selective pre-emergence herbicidal activity The selective pre-emergence herbicidal activity of the compounds of the invention is exemplified by the folacetone solution containing test compound in sufficient quantity to provide the equivalent of about 0.25 to 25 pounds per acre of test compound per cup. The treated cups are then placed on greenhouse benches and cared for in accordance with greenhouse procedures. Three weeks lowing tests in which the seeds of a variety of mono- 5 after treatment, the tests are terminated and each cup is ocotyledonous and dicotyledonous plants are separately examined and rated according to the Herbitoxicity Index mixed with potting soil and planted on top of approxiset forth in the previous example. The tabulated results mately one inch of potting soil in separate pint cups. After of these tests establish the herbicidal proficiency of the planting, the cups are sprayed with the selected aqueoustest compounds and are reported in Table II below.

TABLE II Treat manta Annual weeds Crops Compound acre) KO LA MU PI BA CR GRF W0 MI COR co'r SOY SB WH RA LB SG meg 1609m9900370003- on =o C1 N'CH(0H3)I FHCH 49s999999-t9-99-- N 1s9999999-0009--- CH 0 0 0999ts53-00o3- %3g9-98g3g3g3u8t0 c1 N-CHKCHa):

F CH 499999999ttg79- N 139995g8g8g9 0 0t9---- CZHEO O M 9- 9 9- 0 tq 3a a 0 0 0 0 C1 N-CH(CHa)2 Cl ll 332-233 3-:-3---23 a a a a CH3O\/ =0 gk/lwofiornom 01 1| 0 3 3. 9 33 733 -:-3---s3 a a a a m H-CaH- O \==O 4 C1 N-CH(CH:)2

0 meg 25---=9-----5a----5tu-- H0 o N-CH(CHa)z Br I o a a 0 onto =o 4 C1 N-CH(OHa)z Br I 0 Flog 25---9-----9----wono =0 01 NCH(CH:)2

Br ll F3CH 499998gtg09tgi89 N\ }99-99ta000 0Q zg-a-f-u CHzO I=0 TABLE IICont1nued Treat mag; Annual weeds Crops Compound acre) KO LA MU PI BA CR GRF W MI con 00'1 SOY sB WH RA LB so FBCH 49999aa9mgtaqa 0sga0---- N 19-89309'ma000tc0-- CHaO 'O 01 NCH:

FeCH -9-----3a--1na0- N 011 0 c1 N-CH(CH3): Cl Y e mama-air s c oHao |=0 }8g3%3O00H 0- s o----- K/ (31 ll 0 OFzH 49999sa7 a-9-ee----- N 1979939tgt-t-mc-- CIHEO o %9g5aoao0-0-o----- CF35]! ggg s aaa ss- 9--ac------ m m a 'mc D'c3 70 jf |=O 9a3aosflo-:-o----- NH Cl 0mg 4o0aa0o00-o-0----- HO =0 NH Cl EXAMPLE 3 are broadcast over the plot and dlisked into the soil to assure heavy weed infestation. The plots 5 ft. wide and Selectwe Dre-emergence herbwldal actlvlly 20 ft. long, are then planted with corn, soybeans, liman beans, wheat and sorghum in rows approximately 10 5616611? pfe-emergen ce herplclqal actlvlty of inches apart. When plantings are complete, the plots are P of the p f Invention 15 demonstrafed z sprayed with aqueous solution of the test compounds followlng tests Whefelll test Pompounds using the sprayer to deliver the solutions essentially uni- 50/50 acetone/water solutions and applied [11 dilute f l over the test w Untreated Plots which have f q sollltlon to Seeded Plots W1t h a Standard p been similarly planted are employed as controls. At in- PP I ()Perated as to dehyer 57 gaL/acre of tervals of about twenty-four and forty-seven days after test Solution Whlch P Q equlflalent 0f '70 planting, the plots are examined and rated as a herbicidal 1.5, 2.0 or 3.0 lbs. of active ingredient/ acre of seeded tivity according to the index set forth below. At both plot. The soil is prepared in the normal manner by readings control plots adjacent to test plots are heavily plowing and harrowing. Seeds of the broadleaf weeds infested with all species of the broadleaf weeds and (i.e., pigweed, lambsquarters, smartweed, ragweed and grasses employed in the tests. Data obtained are reported jimpson weed) and grasses (i.e., foxtail and crabgrass) TABLE III First rating 24 days Second rating 47 days Soy- Sor- Soy- Sorllilatts, Wheat Corn beans Corn ghum Wheat Corn beans Corn ghum Compound eel- 1 2 a 4 5 AGW ABW 1 2 3 4 5 AGW .ABW OF; H Y5 2 0 0 0 7 8 x x x x x 7 8 N 1 2 0 2 0 0 9 9 x x x x x 7 8 01130 2 4 0 0 o 2 s 10 I x x x x s 9 a s o o 1 a e 10 I x x x x 9 10 C1 N-i-CzHr on, H 14 a p o 0 0 4 7 8 x x x x x 7 s N 1 4 1 2 0 3 7 10 x x x x x 9 10 CZHBO 0 2 e n 2 0 1 s 10 K x x x x 9 10 L a s o a o a 10 10 1 x a z x 9 10 C1 -i-C|H1 CF; H M 4 0 8 0 1 8 x x x x x 8 8 1 4 0 2 0 2 9 10 x x x x x 9 10 n-C H- O 0 2 3 0 3 0 2 10 K x I x x C1 N-l--C1H OF H M 3 0 2 0 0 6 8 K x x x x 5 9 N 1 5 o 4 0 2 9 9 K x x x x} 5 10 0H=0 -0 134 5 0 2 0 a 9 10 K x x x x s 10 C1 N-see-CJI;

Herbi x ci y Index-Field fine sorghum in rows approximately 10 inches apart. When the 2 :50 effect. )5 corn has grown to approximately 16 inches, the soybeans g; to 3 /2 inches, the sorghum to 8 inches, the wheat to 5 g=i8% ati qn by visual ohsegz'agiglhbnsed oliltledugifln in stand. inches and the weeds to 2 /2 to 3 inches in height, the 5; {,i f}, ;,fim% on and plant planted plots are treated, at constant rates of applicag e gq, A value eta or less is acceptable tor crop selectivitytion, with aqueous-acetone solutions of the test compounds 5: 40 containing 0.5% by vol. of a wetting agent, containing as 9=90% the principal active ingredient dodecyl ether of polyeth- 10 Complete kill.

x= Crop not injured. I=Significant injury.

K= Crop killed.

AGW=Annual grass weeds. ABW=Annual brondleat weeds.

EXAMPLE 4 Selective post-emergence herbicidal activity ylene glycol. Eighteen days after application the plots are examined and rated for herbicidal efiicacy. The rating index used is provided in Example 3 above and the data obtained are provided in Table IV below where it can be seen that eifective control of broadleaf weeds and partial control of grasses is obtained at the A, A: and 1.0 lb./ acre rates. Little or no injury to corn is noted at any of these rates and only very slight detectable injury is noted on sorghum at such rates. Untreated control plots are heavily infested with all species of the broadleaf weeds and grasses used in these tests and identified in Example 3 above.

TABLEIV Soy- Sor- R t Corn Wheat beans Corn ghum 88, Compound lbJacre 1 2 3 4 5 AGW ABW s i tiitiiiifi OHIO? |=o i 1 1o 10 1 4 s 10 i 01 /N-i-CaH1 1 ii in CF; 11 g y o 2 a o 1 5 00 N 5% 0 4 1o 1 2 6 11 C2H6o i=0 1 o 9 10 1 1 e 10 c /'I-GIH1 C] a CF| H y 0 a o 4 N 5% 1 a s 1 1 5 e OHIO o 1 1 9 1 5 10 A /Nsec-CtHa 01 ll 21 22 EXAMPLE 5 18.44; N, 9.06. Found: C, 30.76; H, 2.95; C], 23.22; F, Preparation of 5,5-dibromo-6-hydroxy-3-isopropyl- 18'70;

6-(trifluoromethyl)hydrouracil EXAMPLE 9 H on Preparation of 5,5-dichloro-3-isopropyl-6-(1,3-dichloro-2- N N =0 5 propoxy)-6-(tnfiuoromethyl)hydrouracil B H O N- (CHa)z N- wH. R K

I Br 1 1153-0? ]=0 0 0 10 CPCH C1 NCH(CH3)Z 0.50 gms. of 5-bromo-3-isopropyl-6-(trifiuoromethyl)- uracil is dissolved in 50 ml. of water and treated with bromine while stirring said mixture for 3 hours. A white solid forms in said mixture, is separated from said mixture and recrystallized from chloroform and petroleum ether to give the product which has a melting point of The above compound is prepared following the procedure of Example 8 except replacing methanol with 1,3- dichloro-Z-propanol.

167-168.5 C. and analyses as follows: C H Br F N o z EXAMPLE 10 gglf l fi if g ?g Preparation of 5,5-dichloro-3-(1,2-dichloroisopropyl)-6- EXAMPLE 6 methoxy-6-(trifiuoromethyl)hydrouracil Preparation of 5,5-dich1oro-6-hydoxy-3-isopropyl- 6-(trifluoromethyl)hydrouracil 01130 I 011201 H on H 01 NCH H20 0 =0 01 CHzCl The above compound is prepared following the proce- 1 I dure of Example 8 except that 3-isopropyl-6-(trifiuoromethyl) uracil is replaced by 3-(1,3-dichlor0isopropyl)-6- 3-Isopropyl 6 (trifluorornethyl)uracil (4.0 g., 0.018 (trifluo ometh n iL moles) is suspended in 50 ml. H O. C1 is bubbled into this suspension for 5 hours while maintaining the tempera- EXAMPLE ture below about 50 C. After this time, TLC (2 x 8 Silica Preparation of 5,5-dich1oro-3-(1,2-dihydroxyisopropyl)- mowers): on N-CH(CHa)2 Gel plate, 1:5 HOAc-H) shows one spot for the sus- 6-methoxy-6-(trifluoromethyl)uracil pended solid, and it does not correspond to starting ma- CF H o terial. The solid is removed, and recrystallized from y CHCl to give white solid, m.p. 163-165 C. CHzOH EXAMPLE 7 40 C1 Preparation of 5-chloro 5 methyl 6 hydroxy- 01 A CHOH 3'iSOPTOPY1'6'(trifluommethyl)hydrom'acil The above compound is prepared following the proce- CF H dure of Example 8 except that 3-isopropyl-6-(trifiuoro- H0 N methyl)uracil is replaced by 3-(1,3-dihydroxyisopropyl)- I 6-(trifluoromethyl)uracil. cm- NCH(CH3)2 EXAMPLE 12 01 u Preparation of 5,5-dichloro-3-allyl-6-methoxy-6- 5O (trifluoromethyl)hydrouracil The above compound is prepared following substantially CF H the procedure of Example 6 except that 3-isopropyl-6-(tri- CH o fiuoromethyl)uracil is replaced with 3-isopropyl-5-methyl- 3 F 6-(trifluoromethyl)uracil. O1 N-CH,OH=0H,

EXAMPLE 8 Cl A Preparation of 5:sdichloro3isopmpyl'6'methoxy'fi' The above compound is prepared following the proce- (trifluoromethyl)hydrouracil dure of Example 8 except that 3-isopropy1-6-(trifluoromethyl)uracil is replaced by 3-allyl-6-(trifluoromethyl)- g uracil. or. -o CH O =o EXAMPLE 13 N CH(CHa)2 C12 MGOH C N CH(CH3 2 Preparation of 5,5-dichloro-3-n-l1exyl-6-methoxy-6- (trifluoromethyl)hydrouracil i g OF H a N 3 Isopropyl 6 (trifluoromethyl)uracil (4.0 g., 0.018 cmoy O moles) is dissolved in 50 m1. absolute methanol. Chlorine N C H a 13" is added to this solution and an exotherm occurs, however,

the temperature of the reaction is maintained below about 01 ll 60 C. Chlorine addition is terminated when the exotherm ceases and the methanol is then stripped. The resulting Following the procedure of Example 8, a solution of solid recrystallizes from 1:1 95% EtOHH O to give 0.0038 moles of 3-n-hexyl-6-(trifiuoromethyl)uracil in 5 white product (4.85 g., 83.6% yield), mp. 129-131 C. ml. of methyl alcohol is treated With chlorine gas. A C8H9C12F3N2O calculated: C, 31.09; H, 2.93; Cl, 22.94; F, slight exotherm insues but the reaction mixture is maintain below 30 C. The mixture is then poured into ice and a white precipitate forms having a melting point of 74-77 C. This product, 5,5 dichloro-3-n-hexyl-6-methoxy-6-trifiuoromethyl)-hydrouracil has the following analysis: C H Cl F N O Calculated: C, 39.47; H, 4.69; F, 15.61; Cl, 19.42; N, 7.67; O, 13.14. Found: C, 39.55; H, 4.42; F, 15.83; Cl, 19.41; N, 7.76.

EXAMPLE 14 Preparation of 5,5-dichloro-3-cyclohexyl-6-methoxy- 6- (trifluoromethyl)hydrouracil The above compound is prepared following the procedure of Example 13 except that 3-n-hexyl-6-(trifluoromethy1)uracil is replaced by 3 cyclohexyl-6-(trifluoromethyl)uracil.

EXAMPLE 15 Preparation of 5,5-dichloro-6-ethoxy-3-is0propyl-6- (trifiuoromethyl)hydrouracil or. g

Cl P) Using the procedure of Example 8, 0.0225 moles of 3-i-propyl-6-(trifluoromethyUuracil is dissolved in 150 ml. of absolute ethanol and the mixture treated with chlorine gas. An exotherm results with the temperature of the reaction mixture increasing to 60 C., however, it is not permitted to exceed said temperature. The mixture is stirred, cooled and then poured into water yielding a white precipitate which is separated by filtration from the reaction mixture and has a melting point of 133-135 C. This product, 5,5 dichloro-6-ethoxy-3-isopropyl-6-(trifluoromethyl)hydrouracil, is found to have the following analysis: C H Cl F- N O Calculated: C, 35.63; H, 3.89; Cl, 21.03; F, 16.91; N, 8.31; O, 14.24. Found: C, 35.46; H, 3.75; C], 21.16; F, 16.94; N, 8.31.

EXAMPLE 16 Preparation of 3-sec-butyl-5,5-dichloro-6-methoxy-6- (trifiuoromethyl) hydrouracil A solution of 0.085 moles of 3-sec-butyl-6-(trifiuoromethyl)uracil in absolute methanol is treated with chlorine gas and stirred for 3 hours with the temperature of the reaction mixture maintained below 35 C. The mixture is then poured into300 m1. of water and stirred. A white solid forms and is separated from the mixture. This product, 3 sec-butyl-S,5-dichloro-6-methoxy-6-(trifluoro methyl)hydrouracil, has a melting point of 133-135 C.

EXAMPLE 17 Preparation of 5,5-dichloro-6-methoxy-3-phenyl- G-(trifluoromethyDuracil H or, N onto =0 01 l 24 The above compound is prepared by the chlorination of 3-phenyl-6-(trifiuoromethyl) following the procedure described in Example 16; m.p. 239-241 C.

EXAMPLE 18 Preparation of 5,5-dichloro-6-methoxy-3-methyl-6-(trifiuoromethyl hydrouracil Preparation of 5,5-dibromo-6-methoxy-3-phenyl-6-(trifiuoromethyl hydrouracil The above compound is prepared following the procedure of Example 17 except that 3-phenyl-6-(trifluoromethyl)uracil is brominated instead of chlorinated.

EXAMPLE 20 Preparation of 5,S-dibromo-G-methoxy-3-methyl-6-(trifiuoromethyl)hydrouracil CF; CHsO Br H The above compound is prepared following the procedure of Example 18 except that 3-methyl-6-(trifiuoromethyl)uracil is brominated instead of chlorinated.

EXAMPLES 21 TO 27 The compounds shown below are prepared in accordance with the procedures of Examples 17 and 19 by merely selecting the appropriately substituted 6-(trifluoromethyl)uracil reactant.

Compound 0 F c1130 |=o Example number TABLE-Continued Compound Example number CHaO I EXAMPLE 28 Preparation of 5,5-dichloro-3-isopropyl-6-propoxy-6- (trifiuoromethyl hydrouracil An excess of chlorine gas is bubbled into a solution of 0.009 moles of 3-isopropyl-6-trifiuoromethyluracil in ml. of n-propanol. The temperature of the reaction is maintained below 35 C. and when the exotherm ceases the mixture is poured into water. A white precipitate forms and is separated from the mixture. This product has a melting point of 81-82.5 C. and the following analysis: C H Cl F N O Calculated: C, 37.62; H, 4.31; CI, 20.19; F, 16.23; N, 7.98; O, 13.67. Found: C, 37.61; H, 4.15; Cl, 19.98; F, 16.49; N, 8.01.

EXAMPLE 29 Preparation of S-bromo-S-chloro-B-isopropyl-6-rnethoxy- 6(trifiuoromethyl)hydrouracil and S-bromo-S-chloro- 6-hydroxy-3-isopropyl 6 (trifluoromethyl)hydroura cil or. N or. N orno l=o HO |=o l/N-cmonm and 7k/NCH(CI-Ia)2 01 H or H o 0 10.7 g. of ethyl 3-amino-4,4,4-trifiuorocrotonate in ml. of dimethyl sulfoxide (DMSO) is admixed With 8.5 g. of potassium t-butoxide in 50 ml. of DMSO while maintaining the reaction mixture at C. 5.48 g. of Isopropylisocyanate is then added and the mixture stirred. The mixture is then poured into water and the resulting mixture extracted with ether. The aqueous phase is then acidified to pH 1 with HCl and extracted with ether. After water washing and drying the yellow solid, 3-isopropyl-6-(trifiuoromethyl)uracil, is obtained. 7.4 g. of this product is then dissolved in 0.5 N NaOH (0.04 mole) and 15 ml. of chloroform. Chlorine is then bubbled into the mixture. After stirring for 1 /2 hours sodium bisulfite is added to discharge the color. The aqueous layer is then separated and extracted with chloroform. The chloroform extracts are washed with water and evaporated to dryness. The white solid, 3-isopropyl-5-chloro-6-(trifluoromethyl)uracil, is obtained. This product is then dissolved in methanol and treated with bromine while maintaining the reaction below about 31 C. After stirring the mixture is poured into water. A White solid forms which is collected by filtration and dried. This product, 5-bromo-5-chloro-3-isopropyl 6 methoxy--(trifluoromethyl)hydrouracil, has a melting point of 129134 C. The filtrate from the above separation is then treated with chloroform and then pentane to give a White solid, mp. -178 C. identified as 5-bromo-5-chloro-6-hydroxy-3 -isopropyl- 6- trifluoromethyl) hydrouracil.

EXAMPLE 30 Preparation of 5,5,6-trichloro-3-isopropyl-6-(trifluoromethyl) hydrouracil or. H or.

Preparation of 5,5,6-tribromo-3-isopropyl-6-(trifiuoromethyl)hydrouracil Following the procedure of Example 30, 5,5-dibromo- 3-isopropyl-6-hydroxy 6-(trifluoromethyl)hydrouracil is dissolved in thionylbromide (SOBr and stirred at room temperature for 24 hours. The mixture is then poured into cold water which precipitates the product, 5,5,6-tribromo-3-isopropyl-6-(trifluoromethyl)hydrouracil.

EXAMPLE 32 Preparation of 5,5-dichloro-6-methoxy-6-(trifluoromethyl) hydrouracil Chlorine was bubbled into a solution of 6-trifluoromethyluracil (5.0 g., 028 mole, CL72103) in 50 ml. absolute methanol with cooling to maintain a temperature of 30 C. or less. The addition of chlorine was stopped when the solid obtained by pouring an aliquot of the reaction solution into Water showed no more unreacted starting material as shown by thin layer chromatography. The rest of the reaction solution was poured into water, stirred vigorously, and the resulting shiny white solid removed. After drying with reaction in the vacuum oven 6.43 g. (81.8%) produt was obtained with mp. 206-208 C.

Analysis: Calculated for C ,H ,Cl F N C, 25.64; H, 1.79; CI, 25.23; F, 20.28; N, 9.97. Found: C, 25.58; H, 1.72; Cl, 25.40; F, 20.32; N, 9.82.

EXAMPLE 33 Preparation of 5,5-dichloro-6-ethoxy-6-(trifluoromethyl) hydrouracil Cl g The above compound was prepared following substantially the same procedure as in Example 32 except that the methanol was replaced with ethanol; melting point was EXAMPLE 34 Preparation of 5,5-dichloro-6-propoxy-6-(trilluoromethyl)hydrouracil The above compound was prepared following substantially the same procedure as in Example 32 except that the methanol was replaced with n-propanol; melting point was 151-153 C.

EXAMPLE 35 Preparation of 5,5-dichloro-6-hydroxy-6-(trifluoromethyl) hydrouracil The above compound was prepared following substantially the same procedure as in Example 32 except that the methanol was replaced with water; melting point was 192-194" C.

' EXAMPLE 36 Preparation of -methyl-5,6-dichloro-6-(trifiuoromethyl hydrouracil or, H

our: 01- NH CH3 ('5 28 EXAMPLE 37 Preparation of 5-chloro-5-methyl-6-hydroxy-6-(trifluoromethyl)hydrouraci1 OH; NH

The above compound is prepared following substantially the same procedure as in Example 6 except that the 3 isopropyl-6-(trifluoromethyl)uracil is replaced by 5- methyl-6-(trifluoromethyDuracil.

We claim:

1. A method for the control of undesirable plant species comprising applying to a locus to be protected from said plant species a herbicidally elfective amount of at least one compound represented by the formula:

wherein X is selected from the group consisting of halogen and lower alkyl of C -C Y is halogen; R is selected from the group consisting of halogen, hydroxy, al-koxy of C -C and monoand di-haloalkoxy of C -C and R is selected from the group consisting of hydrogen; alkyl of C -C alkenyl of C -C monoor di-substituted alkyl of C -C having a substituent selected from the group consisting of halogen, hydroxy and lower alkoxy of C C phenyl; cyclohexyl; cyclopentyl; and monoor di-substituted phcnyl having a substituent selected from the group consisting of nitro, halogen, lower alkoxy of C -C monoor di-haloalkoxy of C -C and trifluoromethyl, and the tautomers thereof and the water soluble sodium, potassium and ammonium salts of said compounds and tautomers, wherein said halogen and halo substituents are selected from the group consisting of fluorine, chlorine, bromine and iodine.

2. A method according to claim 1 wherein R is selected from the group consisting of alkoxy, hydroxy, chlorine, fluorine and bromine.

3. A method according to claim 1 wherein the compound is selected from the group consisting of 5,5-dichloro-3-isopropyl-6-methoxy-6 (trifluoromethyl)hydrouracil, 5,5-dichloro-6-ethoxy-3-isopropyl 6 (trifluoromethyl)hydrouracil, 3-sec-butyl-S,5-dichloro-6 methoxy- 6-(trifluoromethyl)hydrouracil, 5,5-dichloro-3-isopropyl- 6-n-propoxy-6 (trifluoromethyl)-hydrouracil and 5,5-dichloro-6-methoxy-6- (trifiuoromethyl) -hydrouracil.

4. A method for the selective post-emergence control of undesirable plant species in the presence of growing crops comprising applying to the foliage of said undesirable plant species a herbicidally effective amount of at least one compound of claim 1.

5. A method according to claim 4 where R is alkoxy.

6. A method according to claim 4 where R is hydroxy.

7. A method for the selective pre-emergence control of undesirable plant species in the presence of crops compris ing applying to soil containing seeds of undesirable plant species and crops a herbicidally effective amount of at least one compound of claim 1.

8. A method according to claim 7 where R is alkoxy.

9. A method according to claim 7 where R is hydroxy.

References Cited UNITED STATES PATENTS JAMES O. THOMAS, 111., Primary Examiner 

1. A METHOD FOR THE CONTROL OF UNDESIRABLE PLANT SPECIES COMPRISING APPLYING TO A LOCUS TO BE PROTECTED FROM SAID PLANT SPECIES A HERBICIDALLY EFFECITVE AMOUNT OF AT LEAST ONE COMPOUND REPRESENT BY THE FORMULA: 